Bone joint replacement and repair assembly and method of repairing and replacing a bone joint

ABSTRACT

A bone joint repair and replacement assembly. A first portion comprising a bone plate is configured to attach to a distal or proximal end of a bone proximate the joint, generally coaxially with an axis defined by the bone. A second portion comprising an articular surface is configured to attach to the first portion, generally normal with respect to the axis, and inserted into the joint. Although versions of the assembly can be configured for use with several different pivotal joints, the invention is particularly suitable for full or partial replacement of an elbow, wherein the articular surface is pivotally attached to the first portion. Another embodiment of the invention is provided to repair a fractured bone head proximate the joint, and still another embodiment of the invention is provided to repair rotator cuff-related shoulder injuries.

DESCRIPTION OF THE INVENTION

The present invention is a divisional of U.S. application Ser. No.15/668,043, filed Aug. 3, 2017; which is a divisional of U.S.application Ser. No. 13/663,129, filed Oct. 29, 2012 (now U.S. Pat. No.9,730,797); which claims the benefit of Provisional Application No.61/552,387, filed Oct. 27, 2011, and of Provisional Application No.61/557,224, filed Nov. 8, 2011, all of the contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention broadly relates to assemblies used in the repairand replacement of pivotal bone joints. More particularly, the presentinvention relates to assemblies for replacement and partial replacementof elbows, joint repair implants for other relatively small pivotaljoints such as wrists, ankles, and knees, repair of fractured bone headsproximate joints, and implants for repair of shoulder rotator cuffinjuries.

BACKGROUND OF THE INVENTION

Inserting implants and replacing pivotal bone joints, particularlyrelatively small joints such as elbows, wrists, ankles, and knees, is adifficult process due to the relatively complex configuration of suchjoints. While all pivotal bone joints are defined by an intersection andcooperation of proximal and distal heads of different bones, heldtogether by a plurality of ligaments, relatively smaller pivotal joints,such as elbows, wrists, ankles, and knees have a large number of bones,including a large number of relatively fine bones, the heads of whichhave many different configurations. Designing a replacement joint, apartial replacement joint, or a repair implant, against which proximaland distal heads with different configurations can articulate smoothlypresents a complex task for joint repair and replacement implantmanufacturers and for orthopedic surgeons.

For example, an elbow comprises a junction of three different bones, theheads of which have different configurations. An upper arm, or humerus,has a distal end, comprising a trochlea and a capitellum, defining onepart of the elbow. A forearm, comprising two bones, a radius and anulna, have proximal heads, defining another part of the elbow. Theproximal head of the ulna includes, on one side a coronoid process, andon an opposite side, an extending olecranon, which cooperate to define atrochlear notch. A trochlea of the distal end of the humerus pivots inthis trochlear notch. In addition, a medullary cavity is an elongatednarrow cavity in the ulna storing bone marrow. The shape, surfaceroughness, and proper articulation of all of these bone components mustbe considered when designing a suitable elbow replacement or partialreplacement assembly. In addition to the heads of these bones, the elbowincludes soft tissue, e.g., ligaments, collagen fibers, and so forthmust be accounted for when designing a suitable replacement or partialreplacement assembly.

Similar issues arise when designing repair or replacement implants forpivotal joints such as wrists, ankle, and knees, which likewise aredefined by cooperation of proximal and distal heads of a plurality ofbones, ligaments, and other soft tissue.

For these and other reasons, it is common in the field when patientsexperience damage to pivotal joints, resulting, e.g., from over-work,hyper-extension, falling, or playing contact sports, to treat the pain,e.g., with pain-killers, heat and cold, and external supports, ratherthan by repairing or replacing the joint.

Another type of problem can occur with a shoulder joint when a patientexperiences an injury to a rotator cuff. Like other joints, the shoulderis defined by cooperation of proximal and distal heads of several bones,e.g., a proximal head of a humerus, a distal head of a clavicle, aGlenoid Socket, and an A.C. socket. Soft tissue includes, among others,a group of muscles and tendons known as a rotator cuff, which stabilizesthe shoulder. A natural upper surface of the humeral head is smooth, andacts as a gliding surface between the humeral head and the rotator cuff.The rotator cuff, however, is subject to damage resulting from, e.g.,over-work, sudden violent movements, attempting to lift an overly-heavyweight, playing contact sports, and so forth. Motion of an injuredrotator cuff across the head of the humerus can be painful. Moreover, ifthe rotator cuff injury is severe or not repaired promptly, a conditionknown as rotator cuff arthropathy may occur, i.e., formation of anarthritic rough area on the humeral head. Movement of soft tissue acrossthis rough bone surface is even more painful.

There is a need for improved assemblies in the field of elbow repair andreplacement, repair implants for other pivotal joints, and assembliesfor repair of rotator cuff injuries, including but not limited torotator cuff arthropathy.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to bone joint replacementand repair assemblies that substantially obviate one or more of theproblems caused by the limitations and disadvantages of the related art.

An elbow replacement assembly in accordance with the present inventionincludes a first component, including a plate portion configured forattachment to a distal end of a humerus, a generally annular first lobeextending from the plate portion, defining a first aperture therein, anda generally annular second lobe extending from the plate portion, spacedfrom the first lobe, defining a second aperture therein, and a secondcomponent including a generally annular head defining a third aperturetherein, insertable between the first and second lobes, the first,second, and third apertures substantially aligning to define a channel,and a pivot pin insertable into the channel to define a pivotal hinge.

The second component further includes one of a stem portion and a plateportion projecting away from the generally annular head portion. Thestem portion can be configured for insertion into a medullary cavity ofan ulna associated with the elbow, and the plate portion can beconfigured for attachment to the exterior of the ulna.

A partial elbow replacement assembly in accordance with another aspectof the present invention includes a plate portion configured forattachment to a distal end of a humerus, the humerus defining an axis,the plate portion positioned substantially coaxially with the axis, anend of the bone plate including first and second spaced apart lobesdefining a yoke portion, and an articular portion pivotally attachablebetween the first and second lobes of the yoke portion, orientedgenerally transverse to the axis, to define a portion of the elbow.

In the partial elbow replacement assembly, the articular portion isconfigured to include at least one of an artificial capitellum and anartificial trochlea, and is configured to be received in a trochlearnotch of an ulna.

A bone joint repair implant assembly in accordance with another aspectof the invention includes a first portion defining a plate portion,configured for attachment to one of a distal end of a bone proximate thejoint and a proximal end of a bone proximate the joint, the bonedefining an axis and the plate portion positioned substantiallycoaxially with the axis, the plate portion having an end portionpositioned proximate the joint, and a second portion attached to the endportion of the plate portion, generally normal with respect to the axis,extending into the joint to define an articular surface. Preferably, abuttress portion is provided between the first portion and the secondportion to support the articular surface.

In the aspect of the present invention described above, the implant maybe configured for a wrist, with the plate portion configured forattachment to a distal end of a radius, and the articular surfaceconfigured as an articular surface for at least one of the plurality ofbones cooperating to define the wrist. Alternatively, the implant may beconfigured for a knee, with the plate portion configured for attachmentto a proximal end of a tibia, and the articular surface configured as anarticular surface for at least one of the plurality of bones cooperatingto define the knee. Alternatively, the implant may be configured for anankle, with the plate portion configured for attachment to a distal endof the tibia, and the articular surface configured as an articularsurface for at least one of the bones cooperating to define the ankle.In one embodiment, when the implant is configured for a wrist, thebuttress may be configured to raise the articular surface to a positionspaced away from the end portion of the plate portion.

A bone repair assembly for repairing a fractured proximal head of abone, e.g., a radius, in accordance with another aspect of the presentinvention, includes a plate portion configured for attachment to aproximal neck of the bone, the bone defining an axis, and the plateportion positioned substantially coaxially with the axis, and agenerally circular cap portion projecting generally normal to the plateportion across the fractured head of the bone.

The generally circular cap portion can be either hollow or solid.Preferably, when the bone head is fractured into a plurality of jaggedfractured bone pieces, the cap portion includes a peripheral edge, withan annular skirt portion depending from the peripheral edge tosubstantially surround the fractured bone pieces. Fasteners canpenetrate the skirt portion to fix the fractured bone pieces in placeunder the cap.

A shoulder joint rotator cuff repair assembly, in accordance withanother aspect of the present invention includes a plate portionconfigured for attachment to a proximal end of a humerus, and aprosthetic articular portion extending from the plate portion,configured to cover a surface portion on the proximal end of the humerusand a humeral head. In addition, the prosthetic articular portion isconfigured to cover a surface portion of the humerus and of the humeralhead damaged as a result of rotator cuff arthropathy. The prostheticarticular portion defines a gliding surface between the humeral head andthe rotator cuff. In an alternate embodiment, an artificial glidingsurface also can be attached to and undersurface of an acromionproximate the humeral head.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory, andare intended to provide a written description of the invention set forthin the claims.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate presently preferred embodimentsof the invention and together with the description, serve to explain theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first component of an elbowreplacement assembly in accordance with the present invention;

FIG. 2 is a perspective exploded-parts view of an elbow replacementassembly in accordance with the present invention;

FIG. 3 is a perspective view of a fully-assembled elbow replacementassembly depicted in FIG. 2;

FIG. 4 is a perspective exploded-parts view of a partial elbowreplacement assembly in accordance with the present invention;

FIG. 5 is a side view of an assembled partial joint replacement assemblyin accordance with the invention pivotally mounted in a trochlear notchof an ulna;

FIG. 6 is a rear perspective view of a bone joint repair implantassembly in accordance with the present invention;

FIG. 7 is a side view of the bone joint repair implant assembly of FIG.6 mounted in a bone joint;

FIG. 8 is a front perspective view of the bone joint repair implantassembly of FIG. 6;

FIG. 9 is a rear perspective view of another embodiment of a bone jointimplant in accordance with the present invention;

FIG. 10 is a front perspective view of the bone joint repair implantassembly of FIG. 9;

FIG. 11 is a side view of the bone joint repair implant assembly of FIG.9 mounted in a bone joint;

FIG. 12 is a perspective view of a proximal head of a bone, e.g., aradius;

FIG. 13 is a perspective view of a proximal head of a bone, e.g., aradius fractured into a plurality of bone fragments;

FIG. 14 is a perspective view of one embodiment of a bone repairassembly for a fractured head of a bone, e.g., a radius in accordancewith the present invention;

FIG. 15 is a side cross-sectional view of the bone repair assembly ofFIG. 14;

FIG. 15A is a side cross-section view of another embodiment of a bonerepair assembly for a fractured head of a bone, e.g., a radius, inaccording with the invention;

FIG. 16 is a perspective view of a bone repair assembly in accordancewith the present invention installed on a fractured proximal head of abone, e.g., a radius;

FIG. 17 is a side view broadly depicting heads of a plurality of bonescooperating to define a shoulder joint;

FIG. 18 is a perspective view of a proximal end of a humerus and ahumeral head, with a damaged portion on a surface thereof resulting fromrotator cuff arthropathy;

FIG. 19 is a perspective view of a shoulder joint rotator cuff repairassembly in accordance with the invention, in contact with the proximalend of the humerus and the humeral head of FIG. 18;

FIG. 20 is a side partial cross-sectional view of the shoulder joint ofFIG. 18, with the shoulder joint rotator cuff repair assembly inaccordance with the invention attached to the proximal end and humeralhead thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the invention, example of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

An exemplary embodiment of an elbow replacement assembly of the presentinvention is shown in FIGS. 1-3, and designated generally by referencenumeral 10. As embodied herein, and referring to FIGS. 1-3, the elbowreplacement assembly 10 includes a first component 12. The firstcomponent 12 includes a plate portion 14, which is configured with arear arcuate face 16, and at least one aperture 18, dimensioned forinsertion therethrough of appropriate fasteners, for attachment of theplate portion 14 to a distal end of a humerus. First component 12further includes a generally annular first lobe 20, defining a firstaperture 22 therein, and a generally annular second lobe 24, spaced fromthe first lobe 20, defining a second aperture 26 therein.

Referring to FIGS. 1-3, the elbow replacement assembly 10 furtherincludes a second component 28. Second component 28 includes a generallyannular head portion 30, defining a third aperture 32 therein. The headportion 30 inserts between the first and second annular lobes 20 and 24,such that the apertures 22, 32, and 26 substantially align with oneanother to define a channel. Annular bushings or washers 31 and 33 alsomay be inserted in the aligned channel. A pivot pin 34 inserts into thechannel to define a pivotal hinge. The second component 28 also includesa tapering tip portion 36, projecting away from the head portion 30. Thetip portion 36 is configured to be inserted in a medullary cavity of anulna associated with the elbow. Alternately, rather than including thetip portion 36 for insertion into the medullary cavity of the ulna, thesecond component could include a plate portion projecting away from thehead portion 30. Such a plate portion could be configured for attachmentto the exterior of the ulna.

Replacement of an elbow with the elbow replacement assembly of FIGS. 1-3includes surgically preparing the elbow for implant of the elbowreplacement assembly 10; attaching the plate portion 14 to a respectivedistal end of a humerus substantially coaxially with an axis A-A′defined by the humerus, with first and second spaced annular lobes 20and 24 extending proximate the distal end of the humerus; insertingannular head 30 between the first and second lobes 20 and 24; insertingthe pivot pin 34 into the channel defined by the aligned apertures 22,32, and 26 to define a pivotal hinge; and inserting the tip portion 36in the medullary cavity of the ulna associated with the elbow, therebydefining a complete elbow replacement assembly.

An exemplary embodiment of a partial elbow replacement assembly inaccordance with the invention is shown in FIGS. 4-5, and is designatedgenerally by reference numeral 40. A partial elbow replacement also isdisclosed in U.S. application Ser. No. 13/282,810, the contents of whichare incorporated herein by reference. As broadly embodied in FIGS. 4-5,the partial elbow replacement assembly 40 includes a bone plate 42,configured for attachment to a distal end of a humerus, substantiallycoaxially with an axis A-A′ defined by the humerus. A distal end of boneplate 42 proximate the elbow joint separates into first and secondspaced-apart lobes 43 and 44, defining a yoke portion 46. An artificialprosthetic articular portion 48 is pivotally attachable with a pivot pin(not shown) between the first and second lobes 43 and 44 through anaperture 49 formed in the prosthetic articular portion 48, at an angle αgenerally transverse to the axis A-A′. Preferably, prosthetic articularportion 48 is made of a relatively strong, corrosion-resistant metal,e.g., titanium, or a suitable strong, corrosion-resistant nickel-alloy.

As broadly embodied in FIGS. 4 and 5, the prosthetic articular portion48 is configured to replace at least one of a natural capitellum andtrochlea associated with the distal end of the humerus in the elbow. Theprosthetic portion 48 includes an artificial capitellum portion 49 a andan artificial trochlea portion 49 b. In addition, as depicted in FIG. 5,the prosthetic articular portion 48 is configured to pivot in atrochlear notch 50 of the ulna, and articulate with respect to a radialhead 52 of the radius. In doing so, the prosthetic articular portion 48serves as a portion of the ulnotrochlear joint and a portion of theradiocapitellar joint.

An exemplary embodiment of a bone joint repair implant assembly inaccordance with another aspect of the present invention is depicted inFIGS. 6-8, and designated generally by the reference numeral 60. Asbroadly embodied in FIGS. 6-8, bone joint repair implant assembly 60includes a first portion 62 defining a plate portion 64, configured witha plurality of apertures 65 dimensioned to receive fasteners 66 (FIG. 6)therethrough for attachment of the plate portion 64 to a neck of arespective bone proximate either a distal end of the bone, or a proximalend of the bone, depending on the particular joint to which the bonejoint repair implant assembly 60 is to be attached. The respective bonedefines an axis A-A′, and the plate portion 64 is positionedsubstantially coaxially with the axis A-A′ proximate the respectivejoint.

Referring to FIGS. 6-8, the bone joint repair implant assembly 60further includes a second portion 68 attached to an end portion 67 ofthe plate portion 64, at an angle α generally normal to the axis A-A′.The second portion 68 is configured to extend into the joint to definean articular surface 70. Articular surface 70 is made of a metal such astitanium, or another suitable bone implant material. As further embodiedin FIGS. 6 and 8, in the case of a wrist implant, the articular surface70 comes into contact with a surface of a volar capsule 75. Preferably,a plurality of openings 73 are defined in the plate portion 64 at theend portion 67. The openings 73 allow for repair of the volar capsule 75to, for example, bone of a distal end of a radius.

Preferably, bone joint repair implant assembly 60 includes an articularsurface support. As broadly embodied in FIGS. 7-8, the articular surfacesupport is defined by a buttress 72 inserted between the first portion62 and the second portion 68, to provide support to the articularsurface 70.

Referring to FIG. 7, because of the need to implant the buttress 72, oneof ordinary skill in the art will understand that implantation of bonejoint repair assembly 60 requires additional surgical preparation of theend of the respective bone proximate the joint prior to attachment ofthe implant.

FIGS. 9-11 broadly depict an alternate embodiment 60 a of the bone jointrepair implant assembly of FIGS. 6-8. In the alternate embodiment 60 aof FIGS. 9-11, two buttresses 72 a and 72 b are provided between thefirst portion 62 and the second portion 68, supporting articular portion70 at an angle β with respect to the first portion 62. As broadlydepicted in FIG. 11, in the case of a wrist implant, the buttresses 72 aand 72 b also are configured and positioned to lift the articularportion 70 up to a position spaced away from the end 67 of the firstportion 62, so that a volar rim 73 and a dorsal rim 73 a do not come incontact with the metal implant. The volar rim 73, and the dorsal rim 73a, therefore, are not covered by the second portion 68, thereby allowingthe volar rim 73 and the distal rim 73 a to contact soft tissue. One ofordinary skill will understand that use of the alternate embodiment 60 aof the bone joint repair implant repair assembly of FIGS. 9-11 willrequire additional surgical preparation of the respective joint forinsertion of the two buttresses 72 a and 72 b.

The bone joint repair implant assemblies 60 and 60 a described above,and broadly depicted in FIGS. 6-11, can be used with several differentpivotal joints, including, but not limited to knees, ankles, and wrists.In the case of a knee, the plate portion 64 is configured for attachmentto a proximal end of a tibia, and the articular surface 70 is configuredas an articular surface for at least one of the plurality of bonesdefining the knee. In an alternate embodiment, when the joint is anankle, the plate portion 64 is configured for attachment to a distal endof a tibia, and the articular surface 70 is configured as an articularsurface for at least one of a plurality of bones defining the ankle. Inyet another alternate embodiment, when the joint is a wrist, the plateportion 64 is configured for attachment to a distal end of a radius, andthe articular surface 70 is configured as an articular surface for atleast one of a plurality of bones defining the wrist. A bone jointimplant replacement assembly similar in function to bone jointreplacement implant assemblies 60 and 60 a is disclosed in U.S.application Ser. No. 13/663,209, by the same inventor, being filedconcurrently herewith, the contents of which are incorporated herein byreference.

In several cases, prior to implanting a repair or replacement of a bonejoint, a surgeon must first repair a cracked or fractured head of one ofa patient's bones cooperating to define the respective joint. Thisprocedure is particularly essential when a head of a bone is fracturedinto a plurality of jagged bone fragments, which can become lodged in,and interfere with, the new artificial joint, or can interfere withligaments and other soft tissue associated with the joint. This issue isparticularly problematic in the case of a full or partial jointreplacement, or in the case of insertion of a repair implant. FIG. 12broadly depicts a proximal head 74 and a neck 76 of a proximal end of aradius associated with an elbow. Although the discussion below, and thebelow disclosure of the preferred embodiment of this aspect of theinvention, relates to a proximal head of a radius proximate an elbow,one of ordinary skill will recognize that the bone head, and the bonehead fracture assembly discussed below can be modified as necessary toapply to a head of any bone proximate a pivotal bone joint. FIG. 13broadly depicts the proximal head 74 of the radius fractured into aplurality of jagged bone fracture pieces 78. This fractured radius headwill require repair prior to insertion of an elbow replacement orpartial replacement assembly, in order to provide a smooth surface tothe proximal head 74 of the radius.

Exemplary embodiments of a bone repair assembly for repairing thefractured bone head are shown in FIGS. 14-16, and designated generallyby reference numeral 80.

As embodied herein, and referring to FIG. 14, the bone repair assembly80 for a fractured bone head, e.g., a proximal head of a radius,includes a plate portion 82 configured for attachment to the neck 76 ofthe bone proximate the fractured head, the bone defining an axis A-A′,and the plate portion disposed generally coaxially with the axis. Theplate portion 82 is configured to engage an extramedullary surface ofthe neck 76 of the radius. The bone repair assembly 80, in accordancewith the invention, further includes a generally circular cap (or head)portion 84 projecting generally normal to the plate portion 82, acrossthe fractured head 74 of the bone. As shown in FIG. 16, the cap portion84 is configured to cover the fractured head 74. The entire bone repairassembly 80 may be made of an absorbable material or other non-metallicmaterial, and the plate portion 82 and the cap portion 84 can be made ofdifferent materials. Such materials may include ceramic. Furthermore,the absorbable material may dissolve entirely or partially.

Preferably, the generally circular cap portion 84 can be either solid orhollow, with the particular embodiment chosen depending on the nature ofthe fracture to bone head 74, and depending on the professional judgmentof the respective surgeon.

The generally circular cap portion 84 further includes a peripheral edge86, and an annular skirt 88 depending from the peripheral edge 86,configured to substantially surround the bone fracture pieces 78.Accordingly, the cap portion 84 can include a cavity C (FIG. 15) forreceiving the bone head 74 and/or the fractured bone pieces 78. Asbroadly depicted in the embodiment of FIG. 16, the peripheral skirt 88can further be configured for attachment with fasteners 89 to the bonefractured bone pieces 78, in order to fix the fractured bone pieces 78in place within the confines of the cap 84, so that the fractured bonepieces 78 will be substantially restricted from interfering with repairor replacement of the joint.

Additionally, as shown in FIG. 15A, an alternate embodiment 80 a of thebone repair assembly can include an intramedullary extension IE andextension portion EP. The intramedullary extension IE extends downwardlyfrom the cap portion 84, and is configured for receipt in the medullarycavity of the radius. Furthermore, the extension portion (orextramedullary extension) EP extends downwardly from the cap portion 84,and is configured to contact the (in similar fashion to the plateportion 82) an extramedullary surface of the neck 76 of the radius.Fasteners (not shown) can be used to join the plate portion 82, theintramedullary extension IE, the extension portion EP, and/or the neck76 to one another.

In another aspect of the present invention, FIGS. 19-20 broadly depictan assembly for the repair of injuries to a shoulder joint, particularlyrotator cuff injuries, and rotator cuff arthropathy. FIG. 17 broadlydepicts a poximal end of a humerus 90 using fasteners (not shown)received through apertures 99 and 100, and a humeral head 92 extendinginto an (unnumbered) shoulder joint. In addition to heads of variousbones, ligaments, muscles, tendons and sockets defining the shoulder,the shoulder is further defined by the rotator cuff (not shown). FIG. 18also broadly depicts an arthritic damaged surface 94 on a surface of thehumerus 90 and the humeral head 92, commonly known as rotator cuffarthropathy, a condition which evolves over time when there is a chronictear of the rotator cuff. The humeral head 92 subluxes proximally andarticulates with an undersurface 93 of an acromion, shown in FIG. 17.Motion of the shoulder in this condition results in painful grindingbetween arthritic damaged surface 94 and the undersurface 93 of theacromion.

An exemplary embodiment of a rotator cuff repair assembly in accordancewith the invention is shown in FIGS. 19-20, and is designated generallyby reference numeral 95.

As broadly embodied in FIGS. 19-20, the rotator cuff repair assembly 95includes a plate portion 96 attachable to a proximal end of the humerus90 using fasteners (not shown) received through apertures 99 and 100,and a generally circular prosthetic articular portion 97 projecting froma proximal end of the plate portion 95.

Preferably, and as broadly depicted in FIG. 19, the prosthetic articularportion 97 has a diameter δ sufficient to cover the damaged portion 94of the humeral head 92. In addition, in accordance with the invention,the prosthetic articular portion 97 is configured to act as a glidingsurface 98 between the humeral head 92 and the rotator cuff. As furtherembodied in FIG. 20, an artificial gliding surface portion 101 may beinstalled on the undersurface 93 of the acromion.

Persons of ordinary skill in the art will recognize that variousmodifications and variations can be made to the preferred embodimentdescribed above, without departing from the spirit or scope of theinvention. The present invention covers any such modifications andvariations, provided they fall within the scope of the claims and theirlegal equivalents.

What is claimed is:
 1. A method of partially replacing a portion of adistal humerus in an elbow joint of a patient, comprising: providing aplate portion configured for attachment to a distal end of a humerus,the plate portion having a first mid-longitudinal axis, a first endalong the first mid-longitudinal axis, an opposite second end along thefirst mid-longitudinal axis, a maximum length between the first end andthe second end along the first mid-longitudinal axis, a maximum widthperpendicular to the maximum length along the first mid-longitudinalaxis, a first plate portion extending from the first end toward thesecond end, and a first lobe portion and a second lobe portion eachextending from the first plate portion, the first lobe portion and thesecond lobe portion being spaced apart to define a yoke portion forreceiving an articular portion, the first lobe portion terminating in afirst end portion, the second lobe portion terminating in a second endportion, the first end portion and the second end portion being spacedapart at the maximum width of the plate portion; providing the articularportion configured for attachment between the first end portion of thefirst lobe portion and the second end portion of the second lobeportion, the articular portion including a first end, an opposite secondend, a second mid-longitudinal axis extending through the first end andthe second end of the articular portion, and an exterior surfaceapproximating at least a portion of a natural articular surface of adistal humerus, the first end of the articular portion beingpositionable at least adjacent a first interior surface of the first endportion of the first lobe portion, and the second end of the articularportion being positionable at least adjacent a second interior surfaceof the second end portion of the second lobe portion; attaching theplate portion to a distal end of a humerus of the patient, the plateportion being oriented generally coaxially with a longitudinal axisdefined by the patient's humerus; attaching the articular portionbetween the first end portion of the first lobe portion and the secondend portion of the second lobe portion with the second mid-longitudinalaxis being generally transverse to the longitudinal axis defined by thepatient's humerus; and positioning a portion of the articular portion ina naturally-occurring trochlear notch of a proximal ulna of thepatient's elbow joint; wherein portions of the exterior surface of thearticular portion include an artificial capitellum sized and shaped toreplace a natural capitellum and an artificial trochlea sized and shapedto replace a natural trochlea of the patient's elbow joint, theartificial trochlea being configured to contact portions of thenaturally-occurring trochlear notch of the proximal ulna of thepatient's elbow joint when the portion of the articular portion ispositioned in the naturally-occurring trochlear notch of the patient'selbow joint.
 2. The method of claim 1, wherein the articular portion ispivotally attached between the first and second lobe portions of theyoke portion.
 3. The method of claim 1, wherein attaching the plateportion to the distal end of the patient's humerus comprises attachingthe first portion of the plate portion to the distal end of thepatient's humerus.
 4. The method of claim 3, wherein the first portionof the plate portion includes a proximal end and an opposite distal end,and each of the first and second lobe portions includes a proximal endand an opposite distal end, the proximal ends of the first and secondlobe portions being attached to the distal end of the first portion ofthe plate portion.
 5. The method of claim 4, wherein the first lobeportion includes a first lobe mid-longitudinal axis and the second lobeportion includes a second lobe mid-longitudinal axis, the first andsecond lobe mid-longitudinal axes being arranged at an acute angle withrespect to one another.
 6. The method of claim 5, wherein the first endportion of the first lobe portion includes a first aperture therein, thesecond end portion of the second lobe portion includes a second aperturetherein, the first and second apertures being configured to receive atleast one fastener inserted therethrough to facilitate attachment of thearticular portion between the first end portion of the first lobeportion and the second end portion of the second lobe portion.
 7. Apartial elbow replacement assembly, comprising: a plate portion having afirst mid-longitudinal axis, a first end along the firstmid-longitudinal axis, an opposite second end along the firstmid-longitudinal axis, a maximum length between the first end and thesecond end along the first mid-longitudinal axis, a maximum widthperpendicular to the maximum length along the first mid-longitudinalaxis, a first plate portion extending from the first end toward thesecond end, and a first lobe portion and a second lobe portion eachextending from the first plate portion, the first lobe portion and thesecond lobe portion being spaced apart to define a yoke portion forreceiving an articular portion, the first lobe portion terminating in afirst end portion, the second lobe portion terminating in a second endportion, the first end portion and the second end portion being spacedapart at the maximum width of the plate portion; and an articularportion configured for attachment between the first end portion of thefirst lobe portion and the second end portion of the second lobeportion, the articular portion including a first end, an opposite secondend, a second mid-longitudinal axis extending through the first end andthe second end of the articular portion, and an exterior surfaceapproximating at least a portion of a natural articular surface of adistal humerus, the first end of the articular portion beingpositionable at least adjacent a first interior surface of the first endportion of the first lobe portion, and the second end of the articularportion being positionable at least adjacent a second interior surfaceof the second end portion of the second lobe portion; wherein portionsof the exterior surface of the articular portion include portions of anartificial capitellum sized and shaped to replace a natural capitellumand an artificial trochlea sized and shaped to replace a naturaltrochlea of a patient's elbow joint, the artificial trochlea configuredto contact portions of a naturally-occurring trochlear notch of aproximal ulna of the patient's elbow joint when a portion of thearticular portion is positioned in the naturally-occurring trochlearnotch.
 8. The partial elbow replacement assembly of claim 7, wherein thearticular portion is pivotally attached to the first end portion of thefirst lobe portion and the second end portion of the second lobeportion.
 9. The partial elbow replacement assembly of claim 8, whereinthe first lobe portion of the plate portion includes a first lobemid-longitudinal axis and the second lobe portion of the plate portionincludes a second lobe mid-longitudinal axis, the first and second lobemid-longitudinal axes being arranged at an acute angle with respect toone another.
 10. The partial elbow replacement assembly of claim 9,wherein the first end portion of the first lobe portion includes a firstaperture therein, the second end portion of the second lobe portionincludes a second aperture therein, the first and second apertures beingconfigured to receive at least one fastener inserted therethrough tofacilitate attachment of the articular portion between the first endportion of the first lobe portion and the second end portion of thesecond lobe portion.
 11. A partial elbow replacement assembly,comprising: a plate portion being configured for attachment relative toa humerus, the plate portion having at least a first lobe portion and asecond lobe portion extending outwardly from the remainder of the plateportion, each of the first lobe portion and the second lobe portionincluding a proximal end and an opposite distal end, the first lobeportion terminating in a first end portion at and adjacent the secondend thereof, the second lobe portion terminating in a second end portionat and adjacent the second end thereof, the first lobe portion and thesecond lobe portion being spaced apart to form a yoke portion forreceiving an articular portion; and an articular portion configured forattachment between the first end portion of the first lobe portion andthe second end portion of the second lobe portion, respectively, thearticular portion including a first end, an opposite second end, a firstmid-longitudinal axis extending through the first end and the second endof the articular portion, and an exterior surface approximating at leasta portion of a natural articular surface at a distal end of the humerus;wherein portions of the exterior surface of the articular portioninclude portions of an artificial capitellum sized and shaped to replacea natural capitellum and an artificial trochlea sized and shaped toreplace a natural trochlea of a patient's elbow joint, the artificialtrochlea being configured to contact portions of a naturally-occurringtrochlear notch of a proximal ulna of the patient's elbow joint when aportion of the articular portion is positioned in thenaturally-occurring trochlear notch.
 12. The partial elbow replacementassembly of claim 11, wherein the articular portion is pivotallyattached to the first end portion of the first lobe portion and thesecond end portion of the second lobe portion.
 13. The partial elbowreplacement assembly of claim 12, wherein the first lobe portionincludes a first lobe mid-longitudinal axis and the second lobe portionincludes a second lobe mid-longitudinal axis, the first and second lobemid-longitudinal axes being arranged at an acute angle with respect toone another.
 14. The partial elbow replacement assembly of claim 13,wherein the first end portion of the first lobe portion includes a firstaperture therein, the second end portion of the second lobe portionincludes a second aperture therein, the first and second apertures beingconfigured to receive at least one fastener inserted therethrough tofacilitate attachment of the articular portion between the first endportion and the second end portion of the plate portion.
 15. The partialelbow replacement assembly of claim 11, wherein, after receipt of thearticular portion within the naturally-occurring trochlear notch of theproximal ulna, the articular portion is pivotal with respect to theplate portion.
 16. The partial elbow replacement assembly of claim 15,wherein, after receipt of the articular portion within thenaturally-occurring trochlear notch of the proximal ulna, portions ofthe proximal ulna are received between the first lobe portion and thesecond lobe portion.